Electrochemical assembly of poly (diphenylamine)/phosphomolybdic acid/PGE for methanol oxidation

In direct methanol fuel cell (DMFC), methanol is used as a fuel because it can be completely electrooxidized to the final product due to its simple molecular structure. Thus, a great deal of interest exists in the development of materials with a capability for electrocatalytic oxidation of methanol [1,2]. In this work, a layer-by-layer (LbL) film assembly was constructed that comprises alternative layers of poly (diphenylamine) (PDPA) and phosphomolybdic acid (PMA) [3]. First, a layer of oxidized PDPA (referred to as PDPA (+)) was deposited by electropolymerization in constan potential 1.2 V.The constructed electrode was characterized using field emission scanning electron microscopy (FESEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry methods. The cyclic voltammetry of (PDPA/PGE) and (PMA/PDPA/PGE) was recorded in 0.5 M H2SO4 solution containing 1.0 M CH3OH. The effects of various parameters such as the cycle numbers, deposition potential and time in the polymer formation stage and concentration of PMA and also its adsorption time were investigated on the electrode response. This study showed that the modified electrode has good electrocatalytic activity and ability to its application in the DMFC anodes.